I have said over the years and it is true, fat people are the last people on earth that it is ok to openly ridicule. You can't for sex, color, age, sexual identity, but you can for weight - too thin or too fat, for that matter.
And that is because people feel we are lazy for being obese and laziness is a sin.
It is true for some of us, but for most of us, it's so much more than that and they don't have a clue. The worst part about obesity is that we wear our troubles for all to see. There is no hiding it. And that makes those jabs even more painful.
So sorry it happened to you. You have a choice though. You can let it hurt you and stuff that pain with food or do something about it and change your life.